The invention relates to an apparatus for the processing, the possible constriction and possible severance of a strip of plastic materialxe2x80x94particularly a multilayer extruded stripxe2x80x94at specified intervals, with a tool that consists of a plurality of segments that can be moved against each other, as well as the possible simultaneous closure of a casing.
An apparatus of this kind that is used to sever hot plastics pipes is, for example, disclosed in GB-PS 1 109 137.
A similar apparatus for cutting strips of dough to length is shown and described in EP 0 360 446 B.
Although both of these apparatuses are suitable for severing sections of a strip into specified lengths, their design makes them very inflexible.
The purpose of the invention is to create an apparatus of the kind outlined above that can be used flexibly and therefore effectively.
In the solution to this problem proposed by the invention, the tool consists of two sections which can be separated from each other and each of which contains some of the segments.
Since the tool can be separated in the course of the operation, it can be opened further than its segment structure would normally allow, so that it can be deployed for a wide range of different applications.
It is very favourable in this context if in accordance with a further development of the invention two dividable tools are located above each other.
Since the two tools can be divided, they can be opened far enough to permit them to move past each other.
It has proved to be particularly advantageous in this context if in accordance with a further development of the invention the tools are arranged so that they can move vertically.
It is also very advantageous if in accordance with the invention the speed of tool movement can be coordinated with the speed at which the strip is transported.
This makes it possible to produce and transport the strip on a continuous basis, so that it does not have to be slowed down in order to be cut to length.
In a particularly advantageous further development of the invention, tool movement speed and distance and tool closing and opening speed can be coordinated with each other in the movement from the top point to the bottom point.
This means there is no danger that the strip or the severed sections will be affected by the tool, because the latter is already open again when it reaches its bottom point and changes direction and remains open at least to a large extent in accordance with the invention when it completes the movement from ist bottom point to its top point.
In an advantageous further development of the invention, the dividable tool is separated into two parts at least in a middle section of the path it travels from its bottom point to its top point.
It has also proved to be very advantageous if in accordance with the invention the segments of the tool rest against each other with at least one of their surfaces while a further surface is supported against sliding surfaces of a polygonal housing and if an actuating element engages at least one of the segments and is able to move this segment directlyxe2x80x94and the other segments indirectlyxe2x80x94into the closed position and preferably into the open position as well.
This arrangement makes it possible for a single actuating element to move all the segments at least from their open position to their closed position, as the movement of one segment automatically leads to the movement of the other segments by this one segment as well as by the sliding surfaces. If this actuating element is designed in the appropriate way as a combined pushing and pulling element, it can, however, be used to move the segments from the closed position to the open position too.
It is also very advantageous if in accordance with the invention a further actuating element engages one of the segments of the tool and is able to move this segment and thus indirectly the other segments into the open position.
This further actuating element can be used additionally to move the segments of the tool from their closed position to their open position.
In the case of an apparatus with a two-part housing, it is possible in accordance with the invention that an actuating element engages one segment in each of the two halves of the housing and is able to move the segments into their respective closed position and preferably their respective open position as well.
This makes it possible to initiate the movement operation of the segments while the two halves of the housing are still separated from each other.
It has proved to be very favourable in this context if in accordance with the invention a further actuating element engages one segment in each of the two halves of the housing which is able to move this segment and thus indirectly the other segments of this half of the housing into the open position.
If this further actuating element engages a segment that is located on the outside when the housing is open, it helps in addition to hold this segment in position.
It is also very advantageous if in accordance with a further development of the invention a toothed belt is used as actuating element to engage one of the segments.
The almost wear resistant operation of a toothed belt and its low elasticity is advantageous for operations at higher speed.
In an advantageous further development of the invention, the two halves of the housing are attached to moving support columns that are hollow and are provided inside with a drive unit for adjusting the segments.
It has also proved to be very favourable if in accordance with the invention a gatelike program device can be incorporated in the drive facilities for moving the segments, with the help of which the closing and opening movement of the segments is carried out in accordance with the lifting movement of the tool.
The opening and closing movements can be adapted to the specific requirements in each individual case simply by changing this gatelike program device.
It is also very advantageous if an apparatus for the application of closure elements for the constricted strip is provided in the area of the tool. In addition, an apparatus for the application of two closure elements can be provided, where a cutting device severs the constricted strip between the two applied closure elements.
The invention relates to an apparatus to drive a tool in a ring-shaped movement, where the tool is arranged on a lever arm, that is connected to a pivot bearing with its end opposing the tool.
Tools arranged in this way can easily carry a out ring-shaped movement towards the work piece to be processed and back again.
However, this is not sufficient for work pieces that are moved in longitudinal direction during processing. Therefore, in practical operation the work pieces are in most cases stopped during processing.
The purpose of the invention is to describe an apparatus of the mentioned kind which allows to move the work piece in longitudinal direction while the work piece is processed by the tool.
In the solution to this problem proposed by the invention, the pivot bearing allows longitudinal displacement and the lever arm is engaged by a drive unit which, at the the same time, turns the lever arm around the pivot bearing and moves the pivot bearing in longitudinal direction.
Since the slewing movement and the movement in longitudinal direction take place simultaneously, the tool carries out a ring-shaped movement. The tool moves towards the work piece and, at the same time, moves along with it. Then the tool slews away from the work piece and returns to its starting point.
In an advantageous further development of the invention the drive unit has an eccentric design.
Through different embodiments of the eccentricity it is possible to modify the closing movement and the longitudinal movement within wide boundaries.
It has also proved to be very advantageous if in accordance with a further development of the invention, the lever arm is engaged by a knee lever, the first arm of which is pivoted on a lever arm with one end and to a second arm with the other end. The opposing end of the second arm is connected to a stationary pivot, where the drive unit for the lever arm engages through the knee lever.
This way, an exact guidance of the lever arm and a simple initiation of the driving power is ensured.
In another advantageous further development of the invention, a two-armed lever is connected with a first pivot bearing to the first arm of the knee leverxe2x80x94the arm that is allocated to the lever armxe2x80x94and has a second pivot bearing that is at least indirectly stationary pivoted and a third pivot bearing that is driven on a circular orbit.
This way, the drive movement is reduced to a circular movement that can be carried out easily.
Another advantageous further development of the invention is characterized in, that a lever arm is pivoted on the second pivot bearing and that the end of the lever arm opposing the second pivot bearing is stationary pivoted.
Since the length of the lever arm can be adjusted at will, another flexible feature is added to the drive unit.
It has also proved to be very advantageous if in accordance with another further development of the invention, a further lever arm is connected to the third pivot bearing, where this lever arm is connected to a stationary rotary drive with its end opposing the third pivot bearing.
This way, a particularly simple embodiment of the actual drive has been made possible.
It is also very advantageous if the first pivot bearing of the two-armed lever is provided between the two other pivot bearings.
In another advantageous further development of the invention, the application point of the knee lever on the lever arm is designed to allow length adjustments.
This way, the ratio between slewing movement and longitudinal movement can be modified in an easy way with otherwise constant drive unit.
It has also proved to be very advantageous if in accordance with a further development of the invention the stationary pivots are arranged adjustably.
With this too, it is possible to modify both moving directions to each other in an easy way.
In another advantageous further development of the invention, two tools are arranged specularily, the lever arms of which are connceted to a joint pivot bearing.
An embodiment of this kind has proved to be very advantageous, particularly in cases of work pieces that are supposed to be processed on both sides at the same time.
In this context, it is possible in accordance with a further development of the invention that both lever arms are mechanically synchronized by gearwheels and/or lever connections.
Another possibility in accordance with the invention is that a speculary drive unit is arranged on the second lever arm.
This way, it is also possible to control both tools synchronously or differentially.
In another advantageous further development of the invention, the knee levers respectively the lever components themselves are perforated disks.
Moreover, the invention relates to an apparatus for driving and/or guiding a two-piece tool, particularly an apparatus for the processing, the possible constriction and possible severance of a strip of plastic materialxe2x80x94particularly a multilayer extruded stripxe2x80x94at specified intervals, with a tool that consists of a plurality of segments that can be moved against each other, as well as the possible simultaneous closure of a casing.
The purpose of the invention is to create an apparatus of the kind outlined above that allows exact guidance and reliable drive of the tools with relatively simple means.
In the solution to the problem proposed by the invention, each part of the tool is driven and guided along a preset line.
This linear guidance allows an exact determination of the path of the tool parts and can be adapted to the respective requirements.
In an advantageous further development of the invention, the tool parts are arranged on two chainlike drives and/or guiding devices.
In practical operation. chainlike guiding devices have been approved in many fields; sufficiently guided themselves, they can easily be used for additional guiding work. It is furthermore possible to separate the driving and the guiding work at least in sections of the device.
In another advantageous further development of the invention, the drive and guiding devices are arranged parallel to each other and with small distance from each other on at least a section of their path, whereby the tool parts are in working position and interact with each other in this section of the path.
This way, the tool parts are given sufficient time to act on the material to be formed. In addition, this section of the path can be adjusted individually.
It has proved to be very advantageous if in a further development of the invention the two parallel running route sections are arranged vertically.
In this way, it is also possible for a vertically flowing strip from an extrusion die or something similar to be processed easily.
However, in accordance to a further development of the invention, it is also possible to arrange the two parallel running route sections in horizontal direction and to provide a conveyor or something the like for a strip of dough, where the conveyor also has a horizontal section and the speed of which can be adjusted to the speed of the tool parts.
This device is especially suitable for the processing of very delicate material since the undesirable stretching of dough material does not occur.
In another advantageous further development of the invention, the tool parts are connected to lever arms and move on a curve track, where the two curve tracks of the two tool parts overlap along a contact route of the corresponding tool parts and where the tool parts are connected to flexible bearings and are in working position within the contact route.
In an also very advantageous further development of the invention, the tool parts are provided with a drive unit that works with intermitting speeds during the circulation of the tool parts.
In another advantageous further development of the invention, a gatelike program device or something the like is provided at least within the working area of the tool parts to control the segments of the tool parts that can be moved against each other.
Particularly for operations at higher speeds it has proved to be very advantageous, if in accordance with another further development of the invention, both tool parts are connected to flexible bearings and are spring-loaded.
This way, a colliding of the tool parts with all its negative consequences for the entire mechanics is avoided effectively.